Improvement in hardening iron



UNITED STATES PATENT OFFICE.

WILLIAM G. DUNN, OF LA PORTE, INDIANA.

IMPROVEMENT IN HAR DENING IRON.

To all whom it may concern:

Be it known that I, WILLIAM G. DUNN, of La Porte, in the county of La Porte and State of Indiana, have invented certain new and useful Improvements in the Manufacture of Flows and Similar Articles of Cast-Iron; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, making part of this specification, and to the letters of reference marked thereon, like letters indicating like parts wherever they occur.

To enable others skilled in the art to construct and use the invention, I will proceed to describe it.

My invention consists in a novel manner of treating the parts of cast-iron plows and similar implements, whereby they are so hardened as to render them a substitute for the expensive steel plows now in use.

It is well known that in the rich mucky soils of the West no plow or cultivator can be used that does not scour, and that for this reason the ordinary cast-iron plow cannot be used there. This difficulty has necessitated the using of steel plows, which are expensive, and in some soils, of peculiar composition, containing more or less fine gritty material, even steel plows will not answer unless made very hard and finely polished. To overcome these difficulties many plans have heretofore been tried, but hitherto without success, the expensive steel plow still being in universal use.

To obviate these difficulties, and to make cast-iron plows that can be successfully used on these soils, is the object of my invention and this I accomplish in the following manner:

I first form the parts of the plowthat is to say, the mold-board, land-side, and share-Joy casting them of cast-iron in the usual manner. The surface of these parts which is to come in contact with the soil is then ground smooth. The parts are then heated in a clean fire to a red heat, and while thus heated are plunged in to a bath, previously prepared, of the followingingredients: common salt, twelve pounds; saltpeter, four and a half ounces; powdered borax, three and three-fourths ounces; nitric acid, two ounces; muriatic acid, one and a half ounce; salt-water, four gallons; supercarbonate of soda, three and three-fourths ounces; salammoniac, two and a half ounces; sulphuric acid, one and one-fourth ounce.

I permit the iron to remain in the bath until partially or nearly cooled, when it is removed and the surfaces are then polished on an emery- Wheel, which completes the operation.

'It is obvious that cultivator-shares and all similar implements may be treated in. the sam manner, and thus be made of cast-iron instead of steel, as now practiced. By these means I construct plows and similar articles of castiron so hard that they will scour perfectly, and will last for a long time, while costing far less than steel ones.

By actual experiment it is found that plows thus made are fully equal to the best steel and far superior to those made of the poorer qualities of steel.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. The process herein described of treating or hardening the cast-iron parts of plows, cultivator-shares, and similar articles.

2. As a new article of manufacture, plow 1nold-boards,land-sides, or shares, when made of cast-iron treated in the manner herein described.

WILLIAM G. DUNN. Witnesses:

DANIEL NoYEs, E. G. McOoLLUM. 

